Prepare canner, jars, and lids. Wash jars and bands in hot, soapy water, rinse and sterilize in a hot water bath. Use only new lids when canning.
Prepare your peaches. I always start with freestone peaches to make processing easier (freestone peaches pull away from the pit easily where as clingstone peaches, um, cling to the pit. Way more mess. Way less fun.) To peel peaches, submerge them in boiling water for about a minute. Remove from boiling water with a slotted spoon and put them straight into a large bowl with cold water. Then simply peel the skins off by hand. They should come off easily. Slice peaches and discard the pit.
Put sliced peaches into a large, stainless steel pot and turn the heat to medium-high. Add sugar and lemon juice. Cook on medium-high heat, mashing the peaches and stirring frequently to prevent burning, until the peaches have broken down and the sugar has completely dissolved. I like to use an immersion blender to blend the peaches up so there are no large chunks, but you could just use a potato masher to break them down by hand.
Once your peaches have broken down and your jam is the consistency of a sauce, add your chipotle spice and mix well to incorporate the chipotle seasoning throughout the jam. Then, continue cooking until the jam boils down and reaches the consistency you like. I find it takes about 45 minutes in total of cooking on medium high for this jam to thicken up. Continue to stir frequently to prevent burning or sticking to the bottom of the pot.
Once the jam has reached the desired consistency, remove hot jars from canner, skim off any foam that has accumulated on top of the jam and ladle into hot jars leaving ¼-inch headspace at the top. Use a knife to skim around the jar to release any air bubbles. Readjust headspace as needed. Wipe jar rims clean and place lids on top. Screw bands down to fingertip tight.
Place in canner and process in a boiling water bath for 10 minutes. Remove lid and let stand in the canner for 5 minutes before removing and allowing to cool on the counter. Once cool, store in a cool dark place. This jam should store well in your pantry for one to two years.